As title says, my transmission overheats in extreme conditions and trying to decide if a Derale electric fan cooler will help. I have the 6.0 cooler in it, but there are times when pulling a steep grade at low speeds and torque converter unable to lock, my transmission temps have been as high as 240. Anyone have any good experiences with an electric cooling system? Will a larger pan and more fluid help or is that a myth? Mark K. I hope you are still responding to posts. Thanks in advance.

 

Do you also have an Oil to Water cooler?

 

Yes, sorry it is a 2002.

 

What is your rate of return flow? (To see of there is any cooler blockage restricting flow). 1 gallon per minute / 1 quart per 15 seconds is the minimum.

 

Mark K has stated that larger pan does not help keeping the tranny cooler.He said that it only keeps it hot longer.He has done testing and temps under the vehicle are high.

 

I thought I read that from a Mark post as well, every transmission shop I have talked to has advised getting a larger pan. I have not done a flow test, but I don’t believe that is the issue. It only gets hot in extreme conditions and cools right back down. Running down the road pulling trailer it runs in normal temps, just have issues when pulling steep grades at slow speeds.

 

I'm curious what your engine coolant temps are when your transmission temps are at 240.

Does your engine fan clutch engage when you are crawling up hill at slow speeds during "extreme conditions"?

Where are you getting TFT info from? Are you scanning it out of the PCM TFT data or do you have a separate sending unit plumbed into the pressure port, or the pan, or a line in the cooling circuit? If a line, which line?

240 is not catastrophic if transient. That you mention it cools down right away does indicate some cooling circuit flow, but still, I'd check it anyway.

Slow speed lacks air movement, and if your engine clutch fan is not kicking on because the truck sensors are not saying the engine is warm enough to have the fan clutch engaged, then one way to lower transmission temperature would be to find a way to move more air through the transmission cooler, to reject the heat, rather than add fluid, which absorbs heat.

Adding more fluid simply absorbs and carries the heat. If a new pan is installed that added an entire gallon of more fluid capacity to the sump, and the trans pump flow rate is one gallon per minute, then it will take one minute for all the extra fluid to get sheared by the unlocked torque converter, so now there is more fluid that needs heat rejected, and the cycle time for the rest of the fluid to get it's turn through the cooler to get it's heat rejected will take a minute longer too.

If your engine fan isn't moving air in the condition you are operating in (for whatever reason), then you can always add electric fans (an option you were asking about). Note the word "add" does not mean replace. No electric fan can move the air that the engine driven fan can, but supplemental electric fan(s) focused on the transmission oil to air cooler can be turned on ahead of time, in anticipation of the steep grade that the truck can't feel or sense yet. Operator commanded fans can keep the air moving through the heat exchanger when the truck is standing still, nevermind going slow.

Below are photos of the twin electric fans that I close coupled to the transmission cooler on my truck back in 2001...


Above: These were the highest CFM per amp of electrical current consumed available at the time, made by PermaCool (This model is no longer available. sadly)



Above: Upper hand fabricated shroud to force fan air through transmission cooler, rather than allow it to escape through path of lower resistance






Above: Fans not mounted to cooler. Instead, the fans are sturdily attached to the front rad support below. (Power Steering cooler temporarily removed for this install)


Above: Screen baffles installed in gap between lower rad support and fan body, so that fan pulls air through the cooler, rather than from underneath cooler


Above: Bracketry to support upper crossbar that top mounting ears of fan are attached to. No zipties! No fans hanging off the cooling fins!

Fans are thermostatically controlled, but I also have a switch for manual activation, which I use prophylactically when I know that a slow go, no flow challenge is about to be faced. It is easier to prevent heat from accumulating, than to remove heat after the fact.

 

My 2000 does not have the air/water transmission cooling but has never overheated after installing the 6.0 transmission cooler. Have you checked to see that the bypass at the transmission has not stuck open?

@Y2KW57 , tell me more about that winch please. Does it fit behind the factory bumper?

 

@FordTruckNoob yes the Warn M15K winch is mounted in a high strength low alloy steel cradle and fits entirely behind and is hidden by the front bumper, as shown below.



Back on topic... note the transmission cooling scoops between air management valances.

 

Awesome. Did you fabricate the cradle yourself? If so, can you share details please?

 

This is what I was thinking as well. My first check would be the bypass. I have read they are rebuildable. I think there is a write up in the tech folder.

 

I am unable to read coolant temps, my oil temp gets up to around 220 then clutch fan kicks in. I am using the PCM to monitor, I have an Edge CTS2 monitor.

 

I will look into the bypass, but in all other conditions, I have no issues, just the extreme towing issues that I have referenced. I am talking a couple of miles of extreme grades at slow speeds pulling a trailer, which is why I am leaning towards adding an electric fan system. I am not going to add a larger pan per advice from you folks, thanks for that savings.